A light emitting diode (LED) is a cold light emitting element. A light emitting principle of an LED is that, a forward bias (current) is applied to a III-V compound semiconductor material, electrons and holes in a diode are combined to convert energy into light, and light is then emitted when the energy is released. The temperature of an LED does not get high as an incandescent light bulb even when the LED is used for an extended period of time. LEDs feature advantages of having a small volume, a long lifecycle, a low driving voltage, a fast response speed and outstanding shock resistance, can adapt to requirements of being light and compact as well as miniaturization of various apparatus, and are popular products in the daily lives.
To have an LED emit white light, one mainstream approach is producing light in other colors by using fluorescent powder and the light in different colors is blended. However, to prevent an electrode from interfering the applying of fluorescent powder, as shown in FIG. 1 and FIG. 2, an LED structure disclosed includes a negative electrode 1, a substrate 2, an adhesive layer 3, an insulation layer 4, a reflective layer 5, a P-type semiconductor layer 6, a light emitting layer 7, an N-type semiconductor layer 8, and a positive electrode 9. A plurality of through electrodes 10 are used to connect the N-type semiconductor layer 8 and the negative electrode 1 to provide the N-type semiconductor layer 8 with a voltage supply needed. A surface of the N-type semiconductor layer 8 directly serves as a light exiting surface. Thus, the light exiting surface is not provided with any electrode, and is free from the issue of an electrode interfering the applying of fluorescent powder.
Referring to FIG. 3, in the structure shown, a corresponding region 11 of the plurality of through electrodes 10 provided reduces an effective light emitting region of the reflective layer 7, yielding degraded light emitting efficiency and less uniform light emitting effect at a border region 12.